Data retrieved from database with use of servlet (not like your attempt above), returned back or passed to next page where with use of JSTL you would be able to do it much simpler.
You can pick up some general hints and tips from this tutorial

Also when you write something outside the <% %> it is displayed the way you write (HTML style).

So when you write this:

<a href="viewdata.jsp?value1="+sth+">"+ . . .

It will not concat. It is not java and it is not a String to concat it.
If you want to display the value of a variable do this:
<%= rs.getString(1)%>
It will put whatever value it has as "part" of the HTML page.
So might want to write this:

Also make sure to read peter_budo's post and follow his advice. My post was just for informative purposes. It is not correct to open database connections inside a jsp, and use the ResultSet that way to create a link

The changes to internal implementation of the model [business logic + data] which affect the view which shouldn't be the case. Also a design which employs separation of concern is far more easier to maintain, change and troubleshoot.